Knife sharpener

ABSTRACT

A blade sharpening apparatus comprising a rotor, including a plurality of interleaved fingers, operative to interface with the cutting edge of a blade. The rotor is coupled to a rotary drive, such as an electric motor, thereby automating the sharpening process. Preferably, each of the fingers is flexible and includes a lead-in in the form of a radius or chamfer to prevent kick back from the heel of the blade or knife being sharpened. It is also preferable that the sharpening fingers include a portion of abrasive material or surface treatment.

BACKGROUND

Traditionally, knives such as butcher's knives and chefs knives were sharpened or honed using a honing steel and/or whetstone. However, as many people did not have the necessary skill to use such steels to produce good cutting edges on their knives, many different types of knife sharpeners have been developed over the years. While these knife sharpeners are easier to use for the average person, they generally have one or more practical limitations and so there is still a quest to develop an improved knife sharpener. Accordingly, there is a need for a knife sharpener that replicates the honing action of a traditional chef/butcher steel, but with more speed, efficiency and accuracy.

SUMMARY

Provided herein is a blade sharpening apparatus comprising a rotor, including a plurality of interleaved fingers, operative to interface with the cutting edge of a blade. The rotor is coupled to a rotary drive, such as an electric motor, thereby automating the sharpening process. Preferably, each of the fingers is flexible and includes a lead-in in the form of a radius or chamfer to prevent kick back from the heel of the blade or knife being sharpened. It is also preferable that the sharpening fingers include a portion of abrasive material or surface treatment.

The rotor may be formed of a unitary casting or stamping or may be an assembly including first and second rotors. Each rotor could include a hub with a plurality of fingers extending radially therefrom. Each of the rotors is disposed about a rotor shaft such that respective fingers of the first and second rotors are interleaved with one another.

The foregoing and other features, utilities, and advantages of the invention will be apparent from the following more particular description of the embodiment of the invention as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the present invention and together with the description, serve to explain the principles thereof. Like items in the drawings are referred to using the same numerical reference.

FIG. 1 is a top plan view of the blade sharpening apparatus according to the exemplary embodiment shown here with a transparent housing in order to illustrate selected internal components;

FIG. 2 is a side view in elevation of the blade sharpening apparatus shown in FIG. 1;

FIG. 3 is a front view in elevation of the blade sharpening apparatus shown in FIGS. 1 and 2;

FIG. 4 is a perspective view of a representative rotor assembly interfacing with the cutting edge of a knife;

FIG. 5 is a perspective view of the rotor assembly shown in FIGS. 1-3;

FIG. 6 is a front view in elevation of the rotor assembly shown in FIG. 5;

FIG. 7 is a top plan view of the rotor assembly shown in FIGS. 5-6;

FIG. 8 is a front view in elevation of a preferred sharpening finger construction;

FIG. 9 is a cross-sectional view of a sharpening finger taken about line 9-9 of FIG. 8;

FIG. 10 is a perspective view of the rotor assembly shown in FIG. 4;

FIG. 11 is a front view in elevation of the rotor assembly shown in FIGS. 4 and 10;

FIG. 12 is a top plan view of the rotor assembly shown in FIGS. 4, 10-11;

FIG. 13 is a perspective view showing another alternative construction of a rotor assembly;

FIG. 14 is a front view in elevation of the rotor assembly shown in FIG. 13; and

FIG. 15 is a top plan view of the rotor assembly shown in FIGS. 13 and 14.

DETAILED DESCRIPTION

The technology of the present application will be explained with reference to the figures. While the knife sharpener is explained with particular reference to certain devices and materials, it should be understood that those devices and materials are exemplary in nature and should not be construed as limiting.

The disclosed blade sharpening apparatus replicates the honing action of a traditional chef/butcher steel, but with more speed, efficiency and accuracy. The sharpening angles are set by intersecting fingers, eliminating human error that has plagued the traditional manual Steel for many years. The present invention relates to a knife blade sharpener that utilizes overlapping, resiliently flexible fingers or strips, as disclosed in U.S. Pat. No. 6,769,327, which is hereby incorporated by reference in its entirety.

Illustrated in FIG. 1, blade sharpening apparatus 10 includes a housing 12, which supports a rotary drive, such as electric motor 16. Motor 16 is coupled to rotor assembly 20 via shaft 25. The sharpener is powered via cord 14 that may be plugged into a standard wall outlet as is well known in the art. Motor 16 is controlled with buttons 18(1) and 18(2). These buttons are momentary switches that while depressed cause the motor to rotate either clockwise or counterclockwise depending on which button is depressed. When operated by the users left-hand, for instance, the user's thumb would operate momentary switch 18(1) causing the rotor to rotate clockwise as viewed from the front. Conversely if the user is operating sharpener 10 with their right hand then the user would depress momentary switch 18(2) causing the rotor to rotate counter clockwise. Guards 17(1) and 17(2) inhibit the user from depressing the switches with their forefinger and helps protect their thumb. In this way, the sharpener is designed to safely pull the knife away from the user.

Rotor assembly 20 is disposed on shaft 25 and includes first rotor 30(1) and second rotor 30(2) interleaved with each other. Each rotor includes fingers 34(1) and 34(2) respectively. Opposed inwardly facing surfaces of these fingers interface with the blade being sharpened. Rotor assembly 20 rotates within housing 12, which includes slot 13 exposing a portion of rotor assembly 20. Thus, with further reference to FIG. 4, a knife blade 1 may be inserted into slot 13 as rotor assembly 20 is rotating, thereby sharpening the blade. Also shown in FIG. 4 is an alternative construction of the rotor assembly 120. In this perspective view it can be seen how inwardly facing opposed surfaces of the rotor assembly interface with the blade of knife 5. In order to sharpen blade 1 of knife 5 a user grasps handle 3 and inserts blade 1 through slot 13 of housing 12 in order to access the rotor assembly. Rotor assembly 120 rotates in either direction “R” depending on which button is depressed thereby automating the sharpening process. The user grasps handle 3 of knife 5 and translates the knife within slot 13 back-and-forth along direction “X” thereby sharpening the entire length of the blade.

FIG. 5 is a perspective view of rotor assembly 20 shown in more detail. It may be better appreciated here that rotors 30(1) and 30(2) are preferably of the same construction. Thus, each rotor includes a plurality of fingers 34. As perhaps best shown in FIG. 7, respective fingers 34(1) and 34(2) of rotors 30(1) and 30(2) are interleaved with each other creating an included angle “a” operative to interface with the blade to be sharpened. The fingers may form any included angle, or variable angles. The included angle may either stay constant as a knife is pressed down and the fingers flex, or the angle may change. The various arrangements illustrated in the figures may include any number and/or shape of fingers. The fingers can be made of any material, with any abrasive coating or smooth surface, or non-coated material, or mixture of surfaces on the fingers. Preferably, the fingers are at least partially covered with 500 grit industrial diamond coating.

FIG. 8 illustrates a rotor assembly similar to that shown in FIG. 6 with an alternate preferred construction of the sharpening finger 34(2). In this case the sharpening finger includes a pair of lead-ins. As can be seen in FIG. 9 these lead-ins 40 are in the form of a radius. It is important to note that the radius does not extend all the way to the root 44 of the fingers. This construction allows fingers 34 to remain flexible.

FIGS. 10-12 illustrate an alternative construction of rotor assembly 120 introduced in FIG. 4. This construction is similar to that shown and described with respect to FIGS. 5-7. In this case however each finger is narrowed providing an open space between the interleaved fingers. FIGS. 13-15 illustrate yet another alternate construction for rotor assembly 220. In this case, each finger 234 has a spiral construction such that fingers 234 extend radially from their respective hub 235 along an arcuate path.

It should be understood that while the rotor has been described as an assembly, it is contemplated that the rotor could also be formed of a single unitary construction. Such construction could be a casting or stamping formed from sheet-metal. The rotors are preferably formed of a metallic material such as aluminum or steel but could be formed of a suitable plastic material as well. Each finger may include an abrasive material impregnated into the surface or bonded to the surface of each finger. Alternatively the surface of each finger could be disrupted such as by crosshatching as a means to provide an abrasive surface to aid in sharpening the blade.

Accordingly, the present invention has been described with some degree of particularity directed to the exemplary embodiments. It should be appreciated, though, that the present invention is defined by the following claims construed in light of the prior art so that modifications or changes may be made to the exemplary embodiments without departing from the inventive concepts contained herein. 

1. A blade sharpening apparatus comprising: (A) a rotor, including a plurality of interleaved flexible fingers, operative to interface with the cutting edge of a blade; and (B) a rotary drive coupled to said rotor.
 2. A blade sharpening apparatus according to claim 1, wherein said fingers each include a lead-in.
 3. A blade sharpening apparatus according to claim 2 wherein said lead-in is a radius.
 4. A blade sharpening apparatus according to claim 1 wherein said rotary drive is an electric motor.
 5. A blade sharpening apparatus according to claim 1 wherein said fingers are abrasive.
 6. A blade sharpening apparatus comprising: (A) a rotor assembly including first and second rotors, wherein each said rotor includes a hub with a plurality of fingers extending radially therefrom, said rotors being disposed about a rotor shaft such that respective fingers of said first and second rotors are interleaved with one another; and (B) a rotary drive coupled to said rotor shaft.
 7. A blade sharpening apparatus according to claim 6, wherein said fingers are flexible.
 8. A blade sharpening apparatus according to claim 6, wherein said fingers each include a lead-in.
 9. A blade sharpening apparatus according to claim 8, wherein said fingers are flexible.
 10. A blade sharpening apparatus according to claim 9 wherein said lead-in is a radius.
 11. A blade sharpening apparatus according to claim 6 wherein said rotary drive is an electric motor.
 12. A blade sharpening apparatus according to claim 6 wherein said rotor assembly includes an abrasive. 